The Regulator EH range of reheat terminals are constructed from zinc coated sheet steel and fully lined with 5mm thick ceramic fibre board 600mm wide. Transverse Duct Flanges are standard to increase the regidity of the unit and match the VA series VAV terminals when they are bolted together. The heater relay board contains the power relays which switch the electric heater elements. These power relays are silent in operation as compared to contactors and will not fail as solid state relays do when subjected to over heating or lightning strikes. There are three levels of safety interlocks for the electric heater elements. The first level is the velocity sensor and the XC2942 VAV controller which must measure 3 m/s velocity (factory adjustable) before the heater relays are energised. The second and third levels are high limit thermostats set at 900C and 1200C. The 900C high limit will automatically reset after the temperature drops to 750C. The 1200C high limit will lockout and will require manual reseting by turning off the control power to the heater board remotely. This removes the need to obtain access to the ceiling space.